Method for fabricating Z-axis vertical launch

ABSTRACT

An apparatus for automating the fabrication of a copper vertical launch (CVL) within a printed circuit board (PCB) includes a feed mechanism to feed and extrude copper wire from a spool of copper wire and a wire cutting and gripping mechanism to receive copper wire from the feed mechanism, cut and secure a segment of copper wire, insert the segment of copper wire into a hole formed within the PCB, solder an end of the segment of copper wire to a signal trace of the PCB, and flush cut an opposite end of the segment of the copper wire to a surface of the PCB. The wire cutting and gripping mechanism includes a wire cutter to flush cut the segment of copper wire and an integrated heated gripper device to receive the copper wire from the spool of copper wire and cut and grab a segment from copper wire.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 121 as a division ofU.S. patent application Ser. No. 16/541,789, titled “AN APPARATUS FORFABRICATING Z-AXIS VERTICAL LAUNCH WITHIN A PRINTED CIRCUIT BOARD,”filed Aug. 15, 2019, which is incorporated by reference herein in itsentirety for all purposes.

GOVERNMENT RIGHTS

Not applicable.

BACKGROUND

Radio frequency (RF) and electromagnetic circuits may be manufacturedusing conventional printed circuit board (PCB) processes. Some RF andelectromagnetic circuits may include power dividers (power splitters)and combiners, for example, to distribute a signal to many elements,such as radiator elements of an antenna array for beam forming, and/orto combine multiple signals from the elements into one signal.Conventional PCB manufacturing processes may include lamination,electroplating, masking, etching, and others, and may require multiplesteps, expensive and/or hazardous materials, multiple iterations,extensive labor, etc., all leading to higher cost and slower turnaroundtime. Additionally, conventional PCB manufacturing processes havelimited ability to allow for small feature sizes, such as signal tracedimensions, thereby limiting the range of highest frequency signals thatmay be supported by such devices.

The advanced/additive manufacturing technology (AMT) approach is ahybrid additive, subtractive, and conventional approach that removes theplating process used to form interconnections in conventional PCBmanufacturing processes. The process uses two main items to allow theprocess to work, Faraday walls and copper vertical launch (CVL). AFaraday wall is a shielding component that relies on a channel that isfirst milled from the dielectric material, and then a conductive pasteis dispensed into the trench. CVL relies on a soldered copper wireinterface to form an interconnection between two different layers of acircuit board. Automation of both the processes would remove the platingapproach from a printed circuit board process.

Presently, copper vertical launches or CVLs are created by cuttingcopper wire by hand, with the cutters being oriented in a way thatallows a flat cut on one side, then turned the other way to make a flatcut on the other side. There is no automated way to prepare both sidesof copper wire interfaces for a strong solder joint and to install thisinterconnect. Other methods include wire extrusion which can beperformed by specialized equipment such as modified 3D printers, thatare not the most well-known and usually only exist in lab spaces. Solderreflow can be implemented by using a soldering iron, for example. Theclosest mechanism to creating a solder joint in CVLs is in wire bondingapplications.

SUMMARY OF THE DISCLOSURE

One aspect of the present disclosure is directed to an apparatus forautomating the fabrication of a copper vertical launch (CVL) within aprinted circuit board (PCB). In one embodiment, the apparatus comprisesa feed mechanism configured to feed and extrude copper wire from a spoolof copper wire and a wire cutting and gripping mechanism configured toreceive copper wire from the feed mechanism, cut and secure a segment ofcopper wire, insert the segment of copper wire into a hole formed withinthe PCB, solder an end of the segment of copper wire to a signal traceof the PCB, and flush cut an opposite end of the segment of the copperwire to a surface of the PCB.

Embodiments of the apparatus further may include the wire cutting andgripping mechanism having a wire cutter configured to flush cut thesegment of copper wire and an integrated heated gripper device toreceive the copper wire from the spool of copper wire and cut and grab asegment from copper wire. The wire cutter may be mounted on a slide,which is used to position the wire cutter below the wire gripperassembly. The wire gripper assembly may include a pair of gripper jawsand an inverted wire cutter that are used to grip and cut the copperwire, respectively, with the wire feed mechanism being configured todeliver an end of the copper wire into the gripper jaws. The invertedwire cutter may be configured to cut the copper wire from the spool ofcopper wire to create the segment of copper wire, and retract thesegment of copper wire into a wire guide of the wire gripper assembly.The wire gripper assembly further may include a vacuum device or plenumthat has a channel formed there in to channel waste generated fromcutting the copper wire during a trimming operation. The vacuum devicemay be connected to a vacuum source to provide the suction required tomove the waste. The feed mechanism may include a post configured toreceive the spool of copper wire. The feed mechanism further may includea guide, a set of pinch rollers configured to pinch or grab the copperwire, and another guide connected to a flexible tube. The arrangement issuch that copper wire from the spool of wire is fed through the guide,between the pinch rollers, and into the second guide connected to theflexible tube. The wire cutting and gripping mechanism may include awire guide located at an end of a force sensing gripper assembly, withthe wire guide having a diameter that is slightly greater than thediameter of the copper wire being fed into the wire guide. The feedmechanism further may include a stepper motor that drives a gear to feedthe copper wire. The apparatus further may include a PCB reflowpre-heater mechanism configured to reflow solder once the copper wire isinserted into the hole of the PCB. The pre-heater mechanism further mayinclude a hot plate configured to raise a temperature of the PCB to justunder a reflow temperature.

Another aspect of the disclosure is directed a method of automating thefabrication of a copper vertical launch (CVL) within a printed circuitboard (PCB). In one embodiment, the method comprises: feeding copperwire to a wire cutting and gripping mechanism; cutting and securing asegment of copper wire; inserting the segment of copper wire into a holeformed within the PCB; soldering an end of the segment of copper wire toa signal trace of the PCB; and flush cutting an opposite end of thesegment of the copper wire to a surface of the PCB.

Embodiments of the method further may include receiving copper wire froma spool of copper wire. The method further may include removing wastegenerated from cutting the copper wire during a trimming operation.Removing waste may include a vacuum device or plenum that has a channelformed there in to channel waste and a vacuum source to provide thesuction required to move the waste. Feeding copper wire may includeguiding the copper wire with a set of pinch rollers configured to pinchor grab the copper wire, and another guide connected to a flexible tube.The method further may include heating the PCB with a PCB reflowpre-heater mechanism configured to reflow solder once the copper wire isinserted into the hole of the PCB.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of at least one embodiment are discussed below withreference to the accompanying figures, which are not intended to bedrawn to scale. The figures are included to provide illustration and afurther understanding of the various aspects and embodiments, and areincorporated in and constitute a part of this specification, but are notintended as a definition of the limits of the disclosure. In thefigures, each identical or nearly identical component that isillustrated in various figures may be represented by a like numeral. Forpurposes of clarity, not every component may be labeled in every figure.In the figures:

FIGS. 1A and 1B are cross-sectional views of a portion of a printedcircuit board (PCB) showing process steps of creating a copper verticallaunch (CVL);

FIG. 2 is a perspective view of an assembled CVL used to connect twotrace signals;

FIG. 3 is a side elevational view of an integrated Z-axis CVLinstallation apparatus of an embodiment of the present disclosure;

FIGS. 4A-4C are schematic views showing a sequence of extruding copperwire and cutting the copper wire;

FIG. 5 is a perspective view of a dual wire cutting and grippingmechanism of an embodiment of the present disclosure;

FIG. 6 is an enlarged perspective view of a portion of the dual wirecutting and gripping mechanism;

FIGS. 7A and 7B are perspective views of a plenum used to vacuum wastematerial;

FIG. 8 is an enlarged perspective view of another portion of the dualwire cutting and gripping mechanism;

FIG. 9 is an enlarged perspective view of another portion of the dualwire cutting and gripping mechanism;

FIG. 10 is an enlarged perspective view of another portion of the dualwire cutting and gripping mechanism; and

FIG. 11 is a schematic view of a heater mechanism of an embodiment ofthe present disclosure.

DETAILED DESCRIPTION

Various aspects and embodiments are directed to compact, low profileelectromagnetic circuits, and improved methods of manufacture of thesame, that allow for small sizes and higher frequencies thanconventional systems and methods. Aspects and examples described provideexamples of fabricating copper vertical launches (CVLs) within a printedcircuit board (PCB) that advantageously apply additive and subtractivemanufacturing techniques to provide low-cost, automated fabrication.Manufacturing processes described herein may be particularly suitablefor fabrication of such circuit structures having small circuit featurescapable of supporting electromagnetic signals in the range of 8 to 75GHz or more, potentially up to 300 GHz or more using suitablesubtractive (e.g., milling, drilling) and additive (e.g., 3-D printing,filling) manufacturing equipment. Electromagnetic circuit structures inaccord with systems and methods described herein may be particularlysuitable for application in 28 to 70 GHz systems, including millimeterwave communications, sensing, ranging, etc. Aspects and embodimentsdescribed may also be suitable for lower frequency applications, such asin the S-band (2-4 GHz), X-band (8-12 GHz), or others. These frequencieswould include Ka-Band (26.5 to 40 GHz), V-Band (40-75 GHz) and W-Band(75-110 GHz) phased array systems.

Still other aspects, examples, and advantages are discussed in detailbelow. Embodiments disclosed herein may be combined with otherembodiments in any manner consistent with at least one of the principlesdisclosed herein, and references to “an embodiment,” “some embodiments,”“an alternate embodiment,” “various embodiments,” “one embodiment” orthe like are not necessarily mutually exclusive and are intended toindicate that a particular feature, structure, or characteristicdescribed may be included in at least one embodiment. The appearances ofsuch terms herein are not necessarily all referring to the sameembodiment. Various aspects and embodiments described herein may includemeans for performing any of the described methods or functions.

It is to be appreciated that embodiments of the methods and apparatusesdiscussed herein are not limited in application to the details ofconstruction and the arrangement of components set forth in thefollowing description or illustrated in the accompanying drawings. Themethods and apparatuses are capable of implementation in otherembodiments and of being practiced or of being carried out in variousways. Examples of specific implementations are provided herein forillustrative purposes only and are not intended to be limiting. Also,the phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use herein of“including,” “comprising,” “having,” “containing,” “involving,” andvariations thereof is meant to encompass the items listed thereafter andequivalents thereof as well as additional items. References to “or” maybe construed as inclusive so that any terms described using “or” mayindicate any of a single, more than one, and all of the described terms.Any references to front and back, left and right, top and bottom, upperand lower, end, side, vertical and horizontal, and the like, areintended for convenience of description, not to limit the presentsystems and methods or their components to any one positional or spatialorientation.

The term “radio frequency” as used herein is not intended to be limitedto a particular frequency, range of frequencies, band, spectrum, etc.,unless explicitly stated and/or specifically indicated by context.Similarly, the terms “radio frequency signal” and “electromagneticsignal” are used interchangeably and may refer to a signal of varioussuitable frequency for the propagation of information-carrying signalsfor any particular implementation. Such radio frequency signals maygenerally be bound at the low end by frequencies in the kilohertz (kHz)range, and bound at the high end by frequencies of up to hundreds ofgigahertz (GHz), and explicitly includes signals in the microwave ormillimeter wave ranges. Generally, systems and methods in accord withthose described herein may be suitable for handling non-ionizingradiation at frequencies below those conventionally handled in the fieldof optics, e.g., of lower frequency than, e.g., infrared signals.

Various embodiments of radio frequency circuits may be designed withdimensions selected and/or nominally manufactured to operate at variousfrequencies. The selection of appropriate dimensions may be had fromgeneral electromagnetic principles and are not presented in detailherein. As mentioned above, the reactive beamformer of embodiments ofthe present disclosure is particularly suited to millimeter-wavefrequencies.

The methods and apparatuses described herein may support smallerarrangements and dimensions than conventional processes are capable.Such conventional circuit boards may be limited to frequencies belowabout 30 GHz. The methods and apparatuses described herein may allow oraccommodate the manufacture of electromagnetic circuits of smallerdimensions, suitable for radio frequency circuits intended to beoperated at higher frequencies, using safer and less complexmanufacturing, and at lower cost.

Electromagnetic circuits and methods of manufacture in accord with thosedescribed herein include various additive manufacturing techniques toproduce electromagnetic circuits and components capable of handlinghigher frequencies, with lower profiles, and at reduced costs, cycletimes, and design risks, than conventional circuits and methods.Examples of techniques include milling of conductive material from asurface of a substrate to form signal traces or apertures ofsignificantly smaller dimensions than allowed by conventional PCBprocesses, milling of one or more substrates to form a trench, using3-dimensional printing techniques to deposit printed conductive inksinto the trench to form a Faraday wall (a continuous electric barrier,as opposed to a series of ground vias with minimum spacingtherebetween), “vertical launch” signal paths formed by milling(drilling) a hole through a portion of substrate and in which a wire isplaced (and/or conductive ink is printed), to make electrical contact toa signal trace disposed on a surface of the substrate (or an opposingsubstrate), which may include forming a Faraday wall around the verticallaunch conducting wire (which may be copper in some embodiments), andusing 3-dimensional printing techniques to deposit printed resistiveinks to form resistive components. Any of the above example techniquesand/or others (e.g., soldering and/or solder reflow), may be combined tomake various electromagnetic components. Aspects and examples of suchtechniques are described and illustrated herein with respect to a radiofrequency interconnect to convey an electromagnetic signal to or from alayer of an electromagnetic circuit, but the techniques described may beused to form various electromagnetic components, connectors, circuits,assemblies, and systems.

Integrated Z-Axis Copper Vertical Launch Installation Apparatus

In one embodiment, a system and method of extruding copper wire tospecified lengths, for the purpose of Z-axis interconnections in PCBs isshown and described herein. Advanced/additive manufacturing technology(AMT) is utilized to enable copper wire to replace electroplated vias inPCBs. In one embodiment, a hole is drilled from the top of the PCB to apad, e.g., a copper pad, on an internal layer of the PCB. The pad ispre-tinned with solder to enable a soldered connection between the wireand the pad during reflow. The wire is inserted and reflowed between thelayers to create the connection.

FIGS. 1A and 1B illustrate such a process. As shown in FIG. 1A, aportion of a multilayer PCB generally indicated at 10 includes threedielectric layers 12, 14, 16 separated by copper layers or traces 18,20, respectively. A hole 22 is drilled through the PCB 10 from the topof the PCB through dielectric layer 12, copper layer 18, and dielectriclayer 14 to a pad 24 created by copper trace 20 provided on an internallayer of the PCB. In another embodiment, a hole can be formed bystacking layers with holes pre-drilled ahead of time, prior to boardlamination. In one embodiment, the pad is pre-tinned with solder toprovide a solder connection when reflowed. As shown in FIG. 1B, a copperwire 26 is inserted into the hole 22 so that an end of the copper wiretouches the pad 24. The PCB 10 is heated to a reflow temperature inwhich the wire 26 is connected to the pad 24 and the conductive trace20. As shown in 1B, solder material 28 may be deposited on top of thecopper wire 26 to secure a component to the PCB, for example.

Referring to FIG. 2, a Z-axis interconnection generally indicated at 30is shown and described. As shown, the Z-axis interconnection 30 providesconnection between a signal trace 32 provided on an upper surface of atop dielectric layer 34 and a signal trace 36 provided on a lowersurface of a bottom dielectric layer 38, which may be internal within aPCB, for example. The Z-axis interconnection 30 can be fabricated byemploying the systems and methods described herein.

There is no integrated approach to installing CVL Z-axisinterconnections on AMT RF CCAs in a production setting. Currentfabrication techniques are performed in a lab setting manually, andpresent automation approaches in the lab are somewhat ad-hoc and do notintegrate all processes into one setup, capable of producing consistentresults in volume. Recently, automation techniques have been applied toallow limited quantities of CVLs to be produced automated in alaboratory setting. Previously, such CVLs were built by hand, which islabor intensive and costly.

Systems and methods of embodiments of the present disclosure enable anintegrated and automated approach to installing the CVL installation byintegrating the following devices and processes. Referring to FIG. 3, anapparatus, generally indicated at 40, is provided to fabricate CVLswithin a PCB. In one embodiment, the apparatus 40 includes a mechanism,generally indicated at 42, to feed and extrude copper wire from a spoolof copper wire. The apparatus 40 further includes a wire cutting andgripping mechanism, generally indicated at 46, with a debris removalfeature to enable perfectly flat terminations on both sides of the wireinterconnect when processed, which is critical to achieving a goodsolder joint connection between the copper wire and the pad. The dualwire cutting and gripping mechanism 46 includes a wire cutter configuredto flush cut the copper wire and an integrated heated gripper device toreceive the copper wire from the spool of wire and cut and grab (secure)a segment from copper wire that is used to form and create a solderjoint formation internal to the printed circuit board. The apparatus 40further includes a PCB reflow pre-heater mechanism, generally indicatedat 52, to reflow the solder once the copper wire is inserted into thehole of the PCB. Embodiments of the systems and methods described hereincreate a strong and compliant Z-axis interconnection and enablesautomation on production-grade equipment.

The apparatus 40 enables the automated assembly of CVLs into PCBs, anddrastically reduces the labor time and cost while increasing the yieldand reliability of the connection.

The apparatus 40 can be integrated into an additive manufacturingsolution to add the capability of embedding conductive copper wires into3D printed parts, a concept that is not available on the additivemarket. Moreover, the systems and methods disclosed herein enable rapidprototyping and enable the AMT process to be performed on a larger scaleand much more quickly. The Z-Axis interconnections eliminate the needfor “wet” plating process or other applications where a solder joint hasto be reflowed internal to another assembly thereby providing a “dry”process. The apparatus and associated method enable copper wire to beextruded to specified lengths, for the purpose of creating Z-Axisinterconnections in PCBs. Such AMT process technologies enable thecopper wire to replace electroplated vias in PCBs.

The systems and methods described herein embody an automated apparatus40 that feeds a wire into hole in PCB, solders the wire to a padinternal to the PCB, and then cuts the wire at a top surface of the PCB.This process solves the problem of having to manually perform thecutting and heating/reflow operations, which are not sustainable orfeasible for production in volume.

Automated Wire Extrusion Mechanism for Z-Axis Interconnections

Embodiments of the present disclosure are directed to systems andmethods of extruding copper wire to specified lengths, for the purposeof Z-Axis interconnections in PCBs. The system that would execute thisprocess effectively places wires between layers in a PCB. The systemincludes stepper motors, which are used to drive a gear or toothedbearing, which in turn drives the copper wire in a controlled manner toa specified length. As described herein, an integrated cutting andgripping mechanism trims the wire to length and squares the ends of thewire before and after each cut. In one embodiment, the system is mountedon a CNC gantry system for the automated placement of the CVLs within aPCB.

Referring to FIG. 3, in one embodiment, the mechanism 42 for feeding andextruding wire includes a wire feed system having a spool 54 of copperwire provided on a post 56. The mechanism 42 further includes a guide58, a set (two) of pinch rollers together indicated at 60 configured topinch or grab the copper wire, and another guide 62 connected to aflexible tube 64. The arrangement is such that copper wire from thespool 54 of wire is fed through the guide 58, between the pinch rollers60, and into the second guide 62 connected to the flexible tube 64. In acertain embodiment, the tube 64 is fabricated from Teflon® material toenable the copper wire to slide easily through the tube. The wire feedsystem is configured to pinch the copper wire, and feed the wire downthe tube 64 to a carbide wire guide 66 associated with the cutting andgripping mechanism 46, which will be described in greater detail below.This wire guide 66 has a diameter that is slightly greater than thediameter of the copper wire being fed into the wire guide. In oneembodiment, the wire guide 66 has a diameter that is 0.002 inches largerthan a diameter of the copper wire.

This approach enables the automated assembly of CVLs into PCBs anddrastically reduces the labor time while increasing the yield andreliability of the connection. In addition, the wire feed system of themechanism 42 can be modified and made more generic as a mechanismconfigured to feed and extrude wire between any two generic locations,not necessarily in a PCB. The mechanism 42 can be integrated into anadditive manufacturing solution to add the capability of embeddingconductive copper wires into 3D printed parts, a concept that is notpresently available on the additive market.

In one embodiment, the mechanism 42 further includes a stepper motor 68that drives a gear which extrudes or otherwise feeds the copper wire.Stepper rotation is used (potentially in collaboration with sensors forfeedback on extrusion distance) to correlate distance extruded. Oncecopper wire is driven to length, automatic flush cutters trim the wire,which will be described in greater detail below. In one embodiment, asecond set of cutters are used to cut the wire from the spool of wireand grab the cut section of wire. In another embodiment, the flushcutters are then flipped to flush cut the wire again in preparation forthe next wire insertion. This process is illustrated sequentially inFIGS. 4A-4C. FIG. 4A illustrates a wire cutter being used to cut excessmaterial from a processed PCB. FIG. 4B illustrates a second wire cutteror an inverted wire cutter being used to cut an end of wire being usedfor the next CVL. FIG. 4C illustrates the end of the wire after beingcut by the inverted wire cutter, with excess material being vacated fromthe area by a vacuum device.

An integrated sensor can be employed to provide a feedback loop to trackand control wire dispensing. Other types of motor drivers, and methodsof gripping the wire for extrusion can be provided.

Dual Wire Cutting and Gripping Mechanism for Z-Axis Interconnections

Known approaches employed to prepare a copper wire to create a Z-axisinterconnection use a single wire cutter that typically produces anuneven and pointed end, resulting in poor soldering joints that affectmechanical and electrical performance of the assembly. Presently, thewire is cut by hand and the cutters are oriented in a way that allows aflat cut on one side, then turned the other way to make a flat cut onthe other side.

Systems and method of embodiments of the present disclosure create flatwire surfaces on both sides of the cut wire segment, enabling strong andcompliant solder joints for Z-axis interconnections in PCBs. In oneembodiment, the cutting and gripping mechanism 46 includes tworetractable cutters, which are oriented in opposite directions to cutthe wire. The dual flush cutting system facilitates a perfect flat crosssection cut, thereby enabling copper vertical interconnection. Themechanism 46 further includes a debris removal vacuum device, whichremoves copper debris thereby providing a solution that can be run in aproduction environment at high rates.

Referring back to FIG. 3, and additionally to FIGS. 5 and 6, the dualwire cutting and gripping mechanism 46 includes a wire flush cutterassembly, generally indicated at 70, force sensing wire gripperassembly, generally indicated at 72, and a digital precision regulator74. The wire cutter assembly 70 includes a wire cutter 76 to cut thewire. In one embodiment, the wire cutter 76 is mounted on a slide 78,which is used to position the wire cutter below the wire gripperassembly 72. The wire gripper assembly 72 has a pair of gripper jaws 80and an inverted wire cutter 82 that are used to grip and cut the copperwire, respectively. The wire feeding and extruding mechanism 42 is usedto place the end of the wire into the gripper jaws 80 of the wiregripper assembly 72. The wire is cut by the inverted wire cutter 82 andthen retracted into the wire guide 66 of the wire gripper assembly 72,and prepared for insertion into the PCB.

Referring to FIGS. 7A and 7B, the wire gripper assembly 72 includes avacuum device or plenum 84 that has a channel 86 formed there in tochannel waste generated from cutting the wire during a trimmingoperation. The vacuum device 84 is connected to a vacuum source toprovide the suction required to move the waste. The wire cutter 76 isretracted up the slide 78, with the wire cutter of the wire cutterassembly 70 remaining out of the way during the remainder of theinsertion process.

In one embodiment, as will be described below with reference to the PCBreflow pre-heater 52, the PCB is placed below the wire guide 66 on aheat plate of the PCB reflow pre-heater, which is used to pre-heat thePCB to 250° C. Referring additionally to FIGS. 8-10, the tooling on thewire gripper assembly 72 are all mounted on an inline linear bearing,and gravity sets the tooling at the bottom of the stroke. A low frictioncylinder coupled to a digital relieving regulator are used to slowlyramp pressure until tooling ascends on the linear bearing when theweight of the tooling is offset, and the system begins to compress alight buffer spring. When the spring is compressed to a preload (setthrough experimentation), the regulator is set at that pressure. Amagnetic linear encoder is mounted to the carriage to measure theposition of the tooling throughout this process, creating a closed loopon the tooling's location.

The wire cutter 76 of the wire cutting assembly 70 and the gripper jaws80 of the wire gripper assembly 72 descend to their respective locationsover the PCB. An ultrasonic sensor is used to position the assemblies ata correct height, and the magnetic linear encoder coupled with a servoaxis close the loop for this operation. This analog ultrasonic sensorallows the system to adapt for thermal expansion of the board and othercomponents in real-time. In close proximity to the PCB, copper wire isfed through the wire guide and started into the hole in the PCB. Thewire guide is retracted away from the PCB while additional wire is fed.This allows the wire to stay started in the PCB hole, but allow room forgripping the wire by the gripper jaws 80 of the wire gripper assembly72.

With the wire guide 66 retracted, the gripper jaws 80 of the wiregripper assembly 72 close on the wire and the servo axis descends withthe wire into the hole. In one embodiment, the gripper jaws 80 areheated to pre-heat the segment of copper wire being held by the gripperjaws. The gripper jaws 80 are mounted to a low force load cell and ispart of a balanced system being held by the buffer spring. As the copperwire makes contact with the solder pad at the bottom of the hole, thebuffer spring begins to collapse, and the servo system balances the loadapplied to the wire while the solder reflow occurs. As the solderreflows, the wire begins descending toward the solder pad on the PCB.The buffer spring begins to unload, and the servo descends further tomaintain downward pressure on the wire column. Using the magnetic linearencoder and the load cell the system will develop a force distance curveshowing a successful deployment of the wire into the solder bump.

The wire is released by the heated gripper jaws 80 of the wire gripperassembly 72. The slide of the wire cutting assembly 70 is used to bringthe custom flush cutter 76 to the wire and the servo axis controls thecut distance from the PCB. The flush cutter 76 closes and cuts the wire.The flush cutter 76 opens, the flush cutter retracts and both servo axisascend to restart the process. The integrated heating mechanismassociated with the gripper jaws, increases the contact surface, therebyimproving heat conduction, and eliminating an extra tool. The mechanism46 combines processes and mechanisms used to automate Z-axisinterconnection for volume production.

This approach enables the automated assembly of CVLs into PCBs, anddrastically reduces the labor time and costs while increasing the yieldand reliability of the connection. In addition, this approach can bemodified and made more generic as a system to extrude wire between anytwo generic locations, not necessarily in a PCB.

The mechanisms of the apparatus 40 can be integrated into an additivemanufacturing solution to add the capability of embedding conductivecopper wires into 3D printed parts, a concept that is not available onthe additive market. Thus, an automated method of extruding and cuttingwires at specified lengths, placed anywhere the gantry can reach, isprovided, especially for applications for placing wires in PCBapplications, mainly for Z-axis interconnections.

Combined with a heating method, the system enables wires to be solderedbetween any two locations.

Heater Mechanism for Z-Axis Interconnections

As described above, systems and methods of extruding copper wire tospecified lengths, for the purpose of Z-axis interconnections in PCBs isdescribed. In one embodiment, a hole is drilled from the top of the PCBto a pad on an internal layer. The pad is pre-tinned with solder. Thewire is inserted and reflowed between the layers. Referring to FIG. 11,in a particular embodiment, the PCB is placed on a hot plate 90 whichbrings the temperature of the PCB to just under reflow temperature. Thewire is driven through a hot end, e.g., a heat block with integratedheating elements associated with the gripper jaws 80 of the wire gripperassembly 72. A tip of assembly is brought to the pre-milled opening,when the wire makes contact with an internally tinned trace the solderreflows. The wire is flush cut as described above and the assembly ismoved away from the apparatus. The solder cools and the copper verticallaunch interconnection is made within the PCB.

No solution exists that is capable of heating and reflowing wire solderconnections. Specifically, there is no known system that is capable ofautomatically heating a wire to solder the wire to create a Z-axisinterconnection in a PCB.

Embodiments of the present disclosure are directed to systems andmethods of placing a workpiece on a heated platform to bring theworkpiece near (but still under) a solder reflow temperature. Wire isdriven through a hot end, e.g., a block of metal with embedded heatingelements, PID controlled, which keeps the workpiece high above thereflow temperature. As the wire is driven through the hot end into thepre-milled hole to the internal copper trace, the wire will contact asolder pad on the internal trace and reflow the solder. At this pointthe wire is flush-cut and the hot-end moves away from the wire to let itcool and solidify.

There doesn't currently exist a solution on the market that is designedfor this problem. Embodiments of the apparatus described herein can beconfigured on a gantry that produces an automated method of fabricatingZ-axis interconnections without the plating process. The function ofdriving a wire through a heated and temperature-controlled heating blockfor the purpose of soldering wire for PCB interconnects producessuperior results.

Having thus described several aspects of at least one embodiment, it isto be appreciated various alterations, modifications, and improvementswill readily occur to those skilled in the art. Such alterations,modifications, and improvements are intended to be part of thisdisclosure and are intended to be within the scope of the disclosure.Accordingly, the foregoing description and drawings are by way ofexample only.

What is claimed is:
 1. A method of automating a fabrication of a coppervertical launch within a printed circuit board (PCB), the methodcomprising: feeding copper wire to a wire cutting and grippingmechanism; cutting and securing a segment of copper wire; inserting thesegment of copper wire into a hole formed within the PCB; soldering anend of the segment of copper wire to a signal trace of the PCB; andflush cutting an opposite end of the segment of the copper wire to asurface of the PCB.
 2. The method of claim 1, wherein feeding copperwire includes receiving copper wire from a spool of copper wire.
 3. Themethod of claim 1, further comprising removing waste generated fromcutting the copper wire during a trimming operation.
 4. The method ofclaim 3, wherein removing waste includes a vacuum device or plenum thathas a channel formed therein to channel waste and a vacuum source toprovide a suction required to move the waste.
 5. The method of claim 1,wherein feeding copper wire includes guiding the copper wire with a setof pinch rollers configured to pinch or grab the copper wire, andanother guide connected to a flexible tube.
 6. The method of claim 1,further comprising heating the PCB with a PCB reflow pre-heatermechanism configured to reflow solder once the copper wire is insertedinto the hole of the PCB.
 7. The method of claim 6, wherein thepre-heater mechanism includes a hot plate configured to raise atemperature of the PCB to just under a reflow temperature.
 8. A methodof fabricating a copper vertical launch within a printed circuit board(PCB) using an apparatus comprising a feed mechanism configured to feedand extrude copper wire from a spool of copper wire, and a wire cuttingand gripping mechanism configured to receive copper wire from the feedmechanism, cut and secure a segment of copper wire, insert the segmentof copper wire into a hole formed within the PCB, solder an end of thesegment of copper wire to a signal trace of the PCB, and flush cut anopposite end of the segment of the copper wire to a surface of the PCB.